Wait till your hip joint goes out and its painful to get on a diamond frame bike..

BITD, for kids there was a Cruiser , 2 bolts on the front and back end of a faux 'gas-tank'

the bike could then be handed down between siblings of opposite genders .

[the third "tube" was added, with out destroying the structural integrity of the step thru frame.]

The Streets of Amsterdam have many men on OMA bikes , when you get mature and marry
it will be good to have that type frame when its your turn to ride the bike
with your child in the seat behind the saddle.